How to add a pontifical document as a an encyclical.

[OSCAR]

I have these question because this kind of documents has not ISBN or ASIN and it is almost impossible to find them out of Internet.

[Emmy]

This is the wrong folder.
See Where should I put my request? (folder overview)

Please MOVE your topic to the correct folder Questions (not edit requests by clicking the (EDIT) button next to the topic's title and picking the target folder from the pulldown list (only available for desktop/laptop, not in the app).

[Javier]

For Roman Catholic encyclicals, there's usually a .pdf version on the Vatican website, we can use that if needed (please link to the full webpage of the encyclical if you'd request the ebook version to be added, not just the .pdf file)

WorldCat is a useful source to get the data for the physical copies as well, (e.g. https://search.worldcat.org/es/title/...). There's no problem with adding an item without ISBN/ASIN, provided it meets the requirements to be considered a published book on GR.